I don't know, but I have just done a physical check of every issue of Modern Roses (I don't have No. 11) and they all, from Modern Roses 1 to 10 showed 'Fraulein Octavia Hesse'. 2007 Modern Roses 12, page 170 showed 'Fraulein Oktavia Hesse'.
Perhaps a German member might enlighten us on H. A. Hesse and his wife who apparently lived in Ems.
The correct name is definitely "Fräulein Octavia Hesse", although German publications are also not consistent. However all early references, as well as a letter of Mr. Hesse to "Deutscher Garten" spell the name with a c.